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Jkei t1_j6hd4kq wrote

Reply to comment by Freedom-No-781 in ELI5 - When losing weight, why is it common to hear "burn more than you consume" in reference to calorie intake. if you consume" 1000 calories, how do you burn 1500? by Freedom-No-781

Just being alive sees you burning something like 1800 calories a day. You'd use that much even if you laid perfectly still in bed all day, like a coma patient.

Say that between an active job and exercise, you burn another 700 or so, putting your total at 2500. If you then stick to a harsh diet like 1000 kcal a day, you're 1500 kcal in the negatives, so that comes from fat instead.

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Freedom-No-781 OP t1_j6hdjt3 wrote

Ohh ok, see I didn't even think about basic bodily needs outside of the gym, that makes it much easier to understand how that's obtained now! So from your example, I could even eat 1500 calories and still lose weight from just normal everyday bodily needs?

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Jkei t1_j6he2oe wrote

Absolutely. As long as total in is smaller than total out, your weight is on a decreasing trend. 1500 in vs 2500 out is still net -1000 which is very substantial.

As a rough estimate, a kilogram of body fat contains about 7000-9000 kcal worth of energy, so this particular diet would see you lose one kg of weight in roughly a week's time.

Similarly, if you were comatose and getting fed 1500 kcal a day, you'd be at 1500 - 1800 = -300, so still losing weight but only 30% as fast as the example diet --> about 1 kg a month.

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Freedom-No-781 OP t1_j6heeiq wrote

Thank you!! This conversation helped so much!

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Jkei t1_j6het39 wrote

No problem, and good luck.

E: do keep an eye on proper macro balance, though.

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annomandaris t1_j6l24wt wrote

Also note that while losing weight is simply calories in > calories out, in the long term there are some factors that can make a difference. First off the longer you spend starving yourself your body will start to slow your metabolism down. Your body wants to keep its fat, it makes you fitter for survival in lean times. So simply starving yourself typically isnt as efficient as doing things like intermittent fasting. Again this doesnt mean that one is better for this person or that person, but just mathematically you can lose more weight that way.

Also remember that even if you are intaking less calories, you still need certain nutrients to be healthy. Your body requires fats, carbohydrates and proteins, as well as nutrients and vitamins to survive.

Unless you are very skilled and knowledgeable about balancing diets and meeting all these requirements and such, cheat days are a benefit to your overall health. Your body will often crave things it needs, so every now and then, you should treat yourself.

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